Direct aging treatment is an important post-processing procedure,yet little research has been done on how it balances the mechanical properties and the stress removal for selective laser melted(SLMed)AlSi10Mg alloys.H...Direct aging treatment is an important post-processing procedure,yet little research has been done on how it balances the mechanical properties and the stress removal for selective laser melted(SLMed)AlSi10Mg alloys.Here,we proposed a typical direct aging treatment on SLMed AlSi10Mg alloys,and studied the effects on their microstructure,properties and residual stress evolution.The results indi-cate that the as-built microstructure is mainly composed of fine cellularα-Al and reticulated Si phases,and some pre-existing precipitates and dislocations are found in these cells.The direct aging treatment promotes the precipitation of nano-scaled Si phases and preserves a network-like Si structure.Therefore,the strength of the peak-aged alloy increases while the ductility decreases.As the aging temperature in-creases from 160 to 200℃,aging hardening behavior was accelerated significantly.Aging at 160℃ for 4-9 h removes 32.0%-43.0%of the residual stress,which is attributed to the decomposition of the su-persaturatedα-Al matrix,the precipitation of the nano-Si phase and the exposure of low-angle grain boundaries(LAGBs).Considering the overal alloy performance obtained,over-aging at 160℃ for 4 h is the optimized heat treatment regime.Under this condition,the yield strength(YS),ultimate tensile strength(UTS)and elongation(EL)of the alloy in the transverse and longitudinal direction are 309.5 MPa,464.4 MPa and 8.3%and 286.4 MPa,464.9 MPa and 5.1%,respectively.展开更多
In this work,a high-strength crack-free TiN/Al-Mn-Mg-Sc-Zr composite was fabricated by laser powder bed fusion(L-PBF).A large amount of uniformly distributed L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles were formed during the...In this work,a high-strength crack-free TiN/Al-Mn-Mg-Sc-Zr composite was fabricated by laser powder bed fusion(L-PBF).A large amount of uniformly distributed L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles were formed during the L-PBF process due to the partial melting and decomposition of TiN nanoparticles under a high temperature.These L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles exhibited a highly coherent lattice relationship with the Al matrix.All the prepared TiN/Al-Mn-Mg-Sc-Zr composite samples exhibit ultrafine grain mi-crostructure.In addition,the as-built composite containing 1.5 wt%TiN shows an excellent tensile prop-erty with a yield strength of over 580 MPa and an elongation of over 8%,which were much higher than those of wrought 7xxx alloys.The effects of various strengthening mechanisms were quantitatively estimated and the high strength of the alloy was mainly attributed to the refined microstructure,solid solution strengthening,and precipitation strengthening contributed by L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles.展开更多
The effects of direct aging treatment(at 300℃ for 5 hours)on selective laser melted(SLMed)Al-4.5Mn-1.5Mg-0.9Sc-0.2Zr alloy were investigated in this work,with the microstructure,fatigue behaviors,and fracture charact...The effects of direct aging treatment(at 300℃ for 5 hours)on selective laser melted(SLMed)Al-4.5Mn-1.5Mg-0.9Sc-0.2Zr alloy were investigated in this work,with the microstructure,fatigue behaviors,and fracture characteristics examined to determine the primary cause of fatigue crack source.The results revealed that the microstructure of the investigated alloy comprised fine equiaxed and columnar grains.Upon aging treatment,a significant number of nano-scaled Al3(Sc,Zr)precipitates were dispersed within the grains,leading to a substantial increase in strengths.The yield strength improved from 431 MPa to 568 MPa,representing an increase of more than 32%,while the fatigue strength improved from 180 MPa to 220 MPa after aging treatment.Nevertheless,the fracture toughness decreased significantly from 25.1 MPa·√m to 12.3 MPa·√m.The results of the fatigue fracture characteristics indicate that the Mn-rich phase and the formation of defects such as pores and poor powder fusion are the sources of fatigue cracking.Although direct aging treatment can significantly increase the yield strength,decrease the rate of fatigue crack propagation,and thus improve the fatigue performance,it deteriorates the fracture toughness,and thus shortens the fatigue life of the alloy as well.展开更多
基金This work was financially supported by Ji Hua Laboratory“Development of additive manufactured core process and special equipment for key parts of aero-engines”(No.X190351TM190)the Basic and Applied Basic Research Foundation of Guangdong Province(No.2022A1515011597).
文摘Direct aging treatment is an important post-processing procedure,yet little research has been done on how it balances the mechanical properties and the stress removal for selective laser melted(SLMed)AlSi10Mg alloys.Here,we proposed a typical direct aging treatment on SLMed AlSi10Mg alloys,and studied the effects on their microstructure,properties and residual stress evolution.The results indi-cate that the as-built microstructure is mainly composed of fine cellularα-Al and reticulated Si phases,and some pre-existing precipitates and dislocations are found in these cells.The direct aging treatment promotes the precipitation of nano-scaled Si phases and preserves a network-like Si structure.Therefore,the strength of the peak-aged alloy increases while the ductility decreases.As the aging temperature in-creases from 160 to 200℃,aging hardening behavior was accelerated significantly.Aging at 160℃ for 4-9 h removes 32.0%-43.0%of the residual stress,which is attributed to the decomposition of the su-persaturatedα-Al matrix,the precipitation of the nano-Si phase and the exposure of low-angle grain boundaries(LAGBs).Considering the overal alloy performance obtained,over-aging at 160℃ for 4 h is the optimized heat treatment regime.Under this condition,the yield strength(YS),ultimate tensile strength(UTS)and elongation(EL)of the alloy in the transverse and longitudinal direction are 309.5 MPa,464.4 MPa and 8.3%and 286.4 MPa,464.9 MPa and 5.1%,respectively.
基金Zhiyu Xiao acknowledges the financial support from the National Natural Science Foundation of China(No.52274363)the Guangdong Basic Applied Basic Research Foundation,China(No.2022A1515010558)+2 种基金Chaofeng Gao acknowledges the financial support by the Guangdong Basic Applied Basic Research Founda-tion,China(No.2022A1515011597)J.T.Zhang acknowledges the financial support by the Guangdong Basic Applied Basic Research Foundation,China(No.2022A1515240065)the Natural Science Foundation Project of Guangzhou,China(No.202201010526).
文摘In this work,a high-strength crack-free TiN/Al-Mn-Mg-Sc-Zr composite was fabricated by laser powder bed fusion(L-PBF).A large amount of uniformly distributed L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles were formed during the L-PBF process due to the partial melting and decomposition of TiN nanoparticles under a high temperature.These L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles exhibited a highly coherent lattice relationship with the Al matrix.All the prepared TiN/Al-Mn-Mg-Sc-Zr composite samples exhibit ultrafine grain mi-crostructure.In addition,the as-built composite containing 1.5 wt%TiN shows an excellent tensile prop-erty with a yield strength of over 580 MPa and an elongation of over 8%,which were much higher than those of wrought 7xxx alloys.The effects of various strengthening mechanisms were quantitatively estimated and the high strength of the alloy was mainly attributed to the refined microstructure,solid solution strengthening,and precipitation strengthening contributed by L1_(2)-Al_(3)(Ti,Sc,Zr)nanoparticles.
基金financially supported by Ji Hua Laboratory“Development of additive manufactured core process and special equipment for key parts of aero-engines”(No.X190351TM190)the Basic and Applied Basic Research Foundation of Guangdong Province(No.2022A1515011597).
文摘The effects of direct aging treatment(at 300℃ for 5 hours)on selective laser melted(SLMed)Al-4.5Mn-1.5Mg-0.9Sc-0.2Zr alloy were investigated in this work,with the microstructure,fatigue behaviors,and fracture characteristics examined to determine the primary cause of fatigue crack source.The results revealed that the microstructure of the investigated alloy comprised fine equiaxed and columnar grains.Upon aging treatment,a significant number of nano-scaled Al3(Sc,Zr)precipitates were dispersed within the grains,leading to a substantial increase in strengths.The yield strength improved from 431 MPa to 568 MPa,representing an increase of more than 32%,while the fatigue strength improved from 180 MPa to 220 MPa after aging treatment.Nevertheless,the fracture toughness decreased significantly from 25.1 MPa·√m to 12.3 MPa·√m.The results of the fatigue fracture characteristics indicate that the Mn-rich phase and the formation of defects such as pores and poor powder fusion are the sources of fatigue cracking.Although direct aging treatment can significantly increase the yield strength,decrease the rate of fatigue crack propagation,and thus improve the fatigue performance,it deteriorates the fracture toughness,and thus shortens the fatigue life of the alloy as well.
